A function has been found in the Apple iPad SDK, which could possibly mean that you would be able to make emergency phone calls on the device. The emergency phone call function was spotted in the SDK when the pass code lock password was entered incorrectly five times.
It is not clear whether this is a function that has been left over from the iPhone OS, or if it is a function that will actually be built into the iPad, which would probably be featured in the 3G models.
The Apple iPad features everything that you would need to make a phone call, which include a speaker, microphone and a 3G connection, although the reason this feature is in there could be that the FCC require any wireless phones to have the ability to make emergency phone calls, even if the phones aren’t activated and haven’t been assigned a telephone number.
This is probably the most plausible reason that this feature has been found inside the Apple iPad SDK, I doubt it will come with the ability to make regular phone calls.